Spinach, caramelized onion, and feta “omelette” for under 400 cals

Ingredients are 2 large eggs, 1/4 yellow onion sliced thin, handful of chopped spinach, and about 15g of crumbled feta.

I usually add diced red pepper but didn’t have any this AM. The feta I use is 90cals per serving but I find half a serving is plenty. This keeps me full for hours!